Probing spin-momentum locking of Weyl nodes with neutron scattering

We explain how a Weyl semimetal phase can be uniquely identified in the differential cross-section measured by an unpolarized neutron experiment. This differential cross-section has unique features that reflect the scattering between Weyl nodes of either same or opposite Chern numbers / spin-momentum locking. Hence, an unpolarized neutron experiment can uniquely identify Weyl semimetals of both inversion-and time-reversal symmetric classes. This is very desirable, as no experimental probe has yet directly confirmed such phases. Further, we describe how the neutron spectrum can distinguish proposed Weyl semimetals from Dirac semimetals.